Ta <sub> 2/3 </ Sub>) O <sub> 3. Of Ba (mg The <sub> 1/3 </ Sub> </ Sub> Microwave Dielectric Ceramics Modified

In recent years, with the rapid development of mobile communication technology, the microwave communication business has also been greatly improved. The researchers used different ways to research the microwave dielectric materials which applied for different frequency. The high frequency microwave dielectric ceramics of complex perovskite structure Ba(Mg_1/3Ta_2/3)O₃(BMT) type were selected as the research objects,and the specimens were prepared by the mixed oxide method. The phase structure, ordering degree, microstructure, Micro-area composition and microwave dielectric properties of BMT materials were investigated by using X-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopy.Processing techniques of BMT ceramics was studied, and the work researched effect of sintering system on the microstructure and microwave dielectric properties. The results show that, the appropriate pre-synthesis temperature plays a key role in guaranteeing the pure phase of BMT ceramic. After sintering at 1600℃and annealing for 6h, the ceramics get a better microwave dielectric properties:εr=25.1 ,Q×f=66000GHz(8GHz),τf=4.5ppm/℃.The influences of B-site, A-site cation additives on the structure and properties of BMT ceramics were investigated in depth. The results showed that:(1) MnCO₃ can low the sintering temperature from 1600℃to 1350℃, and improved the microwave dielectric properties. The B-site ordering degree decreased with MnCO₃ addition increasing, and When MnCO₃ addition achieved 2wt% , its bulk densityρ=7.482g/cm³, its relative density is 98% and BMT got the best microwave dielectric properties:εr=25, Q×f=89000GHz(8GHz),τf=0.5×10^-6/℃. (2) BaWO4 can low the sintering temperature to 1400℃, and improved the microwave dielectric properties. The B-site ordering degree increased with BaWO4 addition increasing, and When BaWO4 addition achieved 4wt% , its bulk densityρ=7.562g/cm³, its relative density is 99% and BMT got the best microwave dielectric properties:εr=26.7,Q×f=98000GHz(8GHz) ,τf=6.5×10^-6/℃. (3) La₂O₃ can low the sintering temperature to 1450℃, and improved the microwave dielectric properties. The B-site ordering degree increased with La₂O₃ addition increasing, and When La₂O₃ addition achieved 4wt% , its bulk densityρ=7.134g/cm³, its relative density is 93.4% and BMT got the best microwave dielectric properties:εr=25.5, Q×f=89000GHz(8GHz),τf=25.3×10^-6/℃. (4) SrCO₃ can low the sintering temperature to 1500℃, and improved the microwave dielectric properties. The B-site ordering degree increased with SrCO₃ addition increasing, and When SrCO₃ addition achieved 6wt% , its bulk densityρ=7.534g/cm³, its relative density is 98.7% and BMT got the best microwave dielectric properties:εr=24.5, Q×f=99000GHz(8GHz),τf=9.6×10^-6/℃.